I have had a pain in my chest for 10 weeks now. I am only 19 years old and would have been able to do exercise all day if I wanted! But now for some reason I find it hard to walk up the stairs, I am light headed, very weak and sometimes find it hard to breath! I have been to my local gp and a cardiac specialist and they say everything is fine but no one has given me a diagnosis! I have done the treadmill test ,echocardiogram, ct scan, chest x ray and bloods and everything is coming back clear. There is no tenderness on the ribcage and the pain is sharp and only lasts for a few seconds but happens about 8 to 10 times a day! As well it feels as if my rib cage is hollow and all thats there is the heart thumping away! So can you tell me what the problem is?